1. Field of the Invention
The present invention relates to microwave ovens, and more particularly, to a magnetron driving circuit board for a microwave oven, in which a magnetron and a magnetron driving circuit are mounted on a single board.
2. Description of the Related Art
In general, a circuit for driving a magnetron in a microwave oven comprises high voltage devices including a high voltage condenser, a high voltage diode, a high voltage transformer, etc. The magnetron driving circuit boosts a commercial alternating current AC voltage to a voltage of 2000 V using the high voltage transformer, boosts the voltage of 2000 V to a voltage of 4000 V required to drive the magnetron, and supplies the voltage of 4000 V to the magnetron.
FIG. 1 is a partially cutaway view showing a construction of a machine room of a conventional microwave oven. As depicted in FIG. 1, an oven body 120 is provided with a cooking cavity 121, and a machine room 122 in which a variety of electric and electronic devices are installed. A door 123 is attached to a front of the cooking cavity 121 to selectively open and close the cooking cavity 121, while a control panel 124 is attached to a front of the machine room 122 to control various operations of the conventional microwave oven. A circuit board 135 is positioned in back of the control panel 124 to control an entire operation of the microwave conventional oven in response to a manipulation of the control panel 124.
High voltage devices including a magnetron 130, a high voltage transformer 131, a high voltage condenser 182, a high voltage diode 184, etc., are installed in the machine room 122. The magnetron 130 receives high voltage power from the high voltage devices 131, 182 and 184, and generates microwaves to irradiate the cooking cavity 121. As a result, food is cooked in the cooking cavity 121 by the microwaves irradiated by the magnetron 130.
Other electric and electronic devices except for the above-described electric and electronic devices, which are required to implement various operations of the microwave oven, are disposed in the machine room 122. A blowing fan 132 is mounted on a back of the machine room 122 to suck outside air and cool the magnetron 130 with the sucked outside air. A noise filter 133 is installed at a position above the blowing fan 132 to eliminate high voltage noise. A power cord 134 is connected to the noise filter 133 to receive power from an outside power source (not shown).
Power and control signals are supplied to the various electric and electronic devices positioned in the machine room 122 through two bundles of wires 140 and 150. The two bundles of wires 140 and 150 are a first bundle of wires 140 and a second bundle of wires 150 that supply the power and control signals to electric and electronic devices positioned on a rear and front portions of the machine room 122, respectively. The first and second bundles of wires 140 and 150 are electrically connected to each other through two terminals 142 and 152.
FIG. 2 is a circuit diagram of the conventional microwave oven, which shows electrical connections between the magnetron 130, the high voltage transformer 131, the high voltage condenser 182, the high voltage diode 184, and the noise filter 133.
A construction of the machine room 122 of the conventional microwave oven is described below. The magnetron 130 and the high voltage devices 131, 182 and 184 are mounted on a wall and a bottom of the machine room 122, respectively. The first and second bundles of wires 140 and 150 are intertwined to connect the magnetron 130 and the high voltage devices 131, 182 and 184 to corresponding locations.
Due to a complicated configuration of the machine room of a conventional microwave oven, an assembly of the machine room requires excessive time in a process of manufacturing the conventional microwave oven. Further, the complicated configuration of the machine room causes utilization of the machine room to be deteriorated, which is a cause of increasing a size of an oven body.